package vals

import "src.elv.sh/pkg/eval/vals"

Package vals contains basic facilities for manipulating values used in the Elvish runtime.

Index

Package Files

aliased_types.go assoc.go bool.go concat.go conversion.go dissoc.go doc.go equal.go feed.go has_key.go hash.go index.go index_list.go index_string.go iterate.go iterate_keys.go kind.go len.go pipe.go reflect_wrappers.go repr.go repr_helpers.go string.go struct_map.go testutils.go

Constants

const NoPretty = math.MinInt32

NoPretty can be passed to Repr to suppress pretty-printing.

Variables

var EmptyList = vector.Empty

EmptyList is an empty list.

var EmptyMap = hashmap.New(Equal, Hash)

EmptyMap is an empty map.

var ErrConcatNotImplemented = errors.New("concat not implemented")

ErrConcatNotImplemented is a special error value used to signal that concatenation is not implemented. See Concat for how it is used.

func Assoc

func Assoc(a, k, v interface{}) (interface{}, error)

Assoc takes a container, a key and value, and returns a modified version of the container, in which the key associated with the value. It is implemented for the builtin type string, List and Map types, StructMap types, and types satisfying the Assocer interface. For other types, it returns an error.

func Bool

func Bool(v interface{}) bool

Bool converts a value to bool. It is implemented for nil, the builtin bool type, and types implementing the Booler interface. For all other values, it returns true.

func CanIterate

func CanIterate(v interface{}) bool

CanIterate returns whether the value can be iterated. If CanIterate(v) is true, calling Iterate(v, f) will not result in an error.

func CheckDeprecatedIndex

func CheckDeprecatedIndex(a, k interface{}) string

CheckDeprecatedIndex checks if the given indexing operation is using any deprecated syntax, and returns a non-empty message if it is.

func Collect

func Collect(it interface{}) ([]interface{}, error)

Collect collects all elements of an iterable value into a slice.

func Concat

func Concat(lhs, rhs interface{}) (interface{}, error)

Concat concatenates two values. If both operands are strings, it returns lhs + rhs, nil. If the left operand implements Concatter, it calls lhs.Concat(rhs). If lhs doesn't implement the interface or returned ErrConcatNotImplemented, it then calls rhs.RConcat(lhs). If all attempts fail, it returns nil and an error.

func Dissoc

func Dissoc(a, k interface{}) interface{}

Dissoc takes a container and a key, and returns a modified version of the container, with the given key dissociated with any value. It is implemented for the Map type and types satisfying the Dissocer interface. For other types, it returns nil.

func Eq

func Eq(r interface{}) tt.Matcher

Eq returns a tt.Matcher that matches using the Equal function.

func Equal

func Equal(x, y interface{}) bool

Equal returns whether two values are equal. It is implemented for the builtin types bool and string, the File, List, Map types, StructMap types, and types satisfying the Equaler interface. For other types, it uses reflect.DeepEqual to compare the two values.

func Feed

func Feed(f func(interface{}) bool, values ...interface{})

Feed calls the function with given values, breaking earlier if the function returns false.

func FromGo

func FromGo(a interface{}) interface{}

FromGo converts a Go value to an Elvish value. Conversion happens when the argument is int, float64 or rune (this is consistent with ScanToGo). In other cases, this function just returns the argument.

func HasKey

func HasKey(container, key interface{}) bool

HasKey returns whether a container has a key. It is implemented for the Map type, StructMap types, and types satisfying the HasKeyer interface. It falls back to iterating keys using IterateKeys, and if that fails, it falls back to calling Len and checking if key is a valid numeric or slice index. Otherwise it returns false.

func Hash

func Hash(v interface{}) uint32

Hash returns the 32-bit hash of a value. It is implemented for the builtin types bool and string, the File, List, Map types, StructMap types, and types satisfying the Hasher interface. For other values, it returns 0 (which is OK in terms of correctness).

func Index

func Index(a, k interface{}) (interface{}, error)

Index indexes a value with the given key. It is implemented for the builtin type string, the List type, StructMap types, and types satisfying the ErrIndexer or Indexer interface (the Map type satisfies Indexer). For other types, it returns a nil value and a non-nil error.

func Iterate

func Iterate(v interface{}, f func(interface{}) bool) error

Iterate iterates the supplied value, and calls the supplied function in each of its elements. The function can return false to break the iteration. It is implemented for the builtin type string, the List type, and types satisfying the Iterator interface. For these types, it always returns a nil error. For other types, it doesn't do anything and returns an error.

func IterateKeys

func IterateKeys(v interface{}, f func(interface{}) bool) error

IterateKeys iterates the keys of the supplied value, calling the supplied function for each key. The function can return false to break the iteration. It is implemented for the Map type, StructMap types, and types satisfying the IterateKeyser interface. For these types, it always returns a nil error. For other types, it doesn't do anything and returns an error.

func Kind

func Kind(v interface{}) string

Kind returns the "kind" of the value, a concept similar to type but not yet very well defined. It is implemented for the builtin nil, bool and string, the File, List, Map types, StructMap types, and types satisfying the Kinder interface. For other types, it returns the Go type name of the argument preceded by "!!".

TODO: Decide what `kind-of` should report for an external command object and document the rationale for the choice in the doc string for `func (ExternalCmd) Kind()` as well as user facing documentation. It's not obvious why this returns "fn" rather than "external" for that case.

func Len

func Len(v interface{}) int

Len returns the length of the value, or -1 if the value does not have a well-defined length. It is implemented for the builtin type string, StructMap types, and types satisfying the Lener interface. For other types, it returns -1.

func MakeList

func MakeList(vs ...interface{}) vector.Vector

MakeList creates a new List from values.

func MakeMap

func MakeMap(a ...interface{}) hashmap.Map

MakeMap creates a map from arguments that are alternately keys and values. It panics if the number of arguments is odd.

func NoSuchKey

func NoSuchKey(k interface{}) error

NoSuchKey returns an error indicating that a key is not found in a map-like value.

func Repr

func Repr(v interface{}, indent int) string

Repr returns the representation for a value, a string that is preferably (but not necessarily) an Elvish expression that evaluates to the argument. If indent >= 0, the representation is pretty-printed. It is implemented for the builtin types nil, bool and string, the File, List and Map types, StructMap types, and types satisfying the Reprer interface. For other types, it uses fmt.Sprint with the format "<unknown %v>".

func ScanToGo

func ScanToGo(src interface{}, ptr interface{}) error

ScanToGo converts an Elvish value to a Go value. the pointer points to. It uses the type of the pointer to determine the destination type, and puts the converted value in the location the pointer points to. Conversion only happens when the destination type is int, float64 or rune; in other cases, this function just checks that the source value is already assignable to the destination.

func ToString

func ToString(v interface{}) string

ToString converts a Value to string. It is implemented for the builtin float64 and string types, and type satisfying the Stringer interface. It falls back to Repr(v, NoPretty).

func TypeOf

func TypeOf(i interface{}) reflect.Type

TypeOf is like reflect.TypeOf, except that when given an argument of nil, it does not return nil, but the Type for the empty interface.

func ValueOf

func ValueOf(i interface{}) reflect.Value

ValueOf is like reflect.ValueOf, except that when given an argument of nil, it does not return a zero Value, but the Value for the zero value of the empty interface.

type Assocer

type Assocer interface {
    // Assoc returns a slightly modified version of the receiver with key k
    // associated with value v.
    Assoc(k, v interface{}) (interface{}, error)
}

Assocer wraps the Assoc method.

type Booler

type Booler interface {
    // Bool computes the truth value of the receiver.
    Bool() bool
}

Booler wraps the Bool method.

type Concatter

type Concatter interface {
    // Concat concatenates the receiver with another value, the receiver being
    // the left operand. If concatenation is not supported for the given value,
    // the method can return the special error type ErrCatNotImplemented.
    Concat(v interface{}) (interface{}, error)
}

Concatter wraps the Concat method. See Concat for how it is used.

type Dissocer

type Dissocer interface {
    // Dissoc returns a slightly modified version of the receiver with key k
    // dissociated with any value.
    Dissoc(k interface{}) interface{}
}

Dissocer wraps the Dissoc method.

type Equaler

type Equaler interface {
    // Equal compares the receiver to another value. Two equal values must have
    // the same hash code.
    Equal(other interface{}) bool
}

Equaler wraps the Equal method.

type ErrIndexer

type ErrIndexer interface {
    // Index retrieves one value from the receiver at the specified index.
    Index(k interface{}) (interface{}, error)
}

ErrIndexer wraps the Index method.

type File

type File = *os.File

File is an alias for *os.File.

type HasKeyer

type HasKeyer interface {
    // HasKey returns whether the receiver has the given argument as a valid
    // key.
    HasKey(interface{}) bool
}

HasKeyer wraps the HasKey method.

type Hasher

type Hasher interface {
    // Hash computes the hash code of the receiver.
    Hash() uint32
}

Hasher wraps the Hash method.

type Indexer

type Indexer interface {
    // Index retrieves the value corresponding to the specified key in the
    // container. It returns the value (if any), and whether it actually exists.
    Index(k interface{}) (v interface{}, ok bool)
}

Indexer wraps the Index method.

type Iterator

type Iterator interface {
    // Iterate calls the passed function with each value within the receiver.
    // The iteration is aborted if the function returns false.
    Iterate(func(v interface{}) bool)
}

Iterator wraps the Iterate method.

type KeysIterator

type KeysIterator interface {
    // IterateKeys calls the passed function with each key within the receiver.
    // The iteration is aborted if the function returns false.
    IterateKeys(func(v interface{}) bool)
}

KeysIterator wraps the IterateKeys method.

type Kinder

type Kinder interface {
    Kind() string
}

Kinder wraps the Kind method.

type Lener

type Lener interface {
    // Len computes the length of the receiver.
    Len() int
}

Lener wraps the Len method.

type List

type List = vector.Vector

List is an alias for the underlying type used for lists in Elvish.

type ListIndex

type ListIndex struct {
    Slice bool
    Lower int
    Upper int
}

ListIndex represents a (converted) list index.

func ConvertListIndex

func ConvertListIndex(rawIndex interface{}, n int) (*ListIndex, error)

ConvertListIndex parses a list index, check whether it is valid, and returns the converted structure.

type ListReprBuilder

type ListReprBuilder struct {
    // contains filtered or unexported fields
}

ListReprBuilder helps to build Repr of list-like Values.

func NewListReprBuilder

func NewListReprBuilder(indent int) *ListReprBuilder

NewListReprBuilder makes a new ListReprBuilder.

func (*ListReprBuilder) String

func (b *ListReprBuilder) String() string

String returns the representation that has been built. After it is called, the ListReprBuilder may no longer be used.

func (*ListReprBuilder) WriteElem

func (b *ListReprBuilder) WriteElem(v string)

WriteElem writes a new element.

type Map

type Map = hashmap.Map

Map is an alias for the underlying type used for maps in Elvish.

type MapReprBuilder

type MapReprBuilder struct {
    // contains filtered or unexported fields
}

MapReprBuilder helps building the Repr of a Map. It is also useful for implementing other Map-like values. The zero value of a MapReprBuilder is ready to use.

func NewMapReprBuilder

func NewMapReprBuilder(indent int) *MapReprBuilder

NewMapReprBuilder makes a new MapReprBuilder.

func (*MapReprBuilder) String

func (b *MapReprBuilder) String() string

String returns the representation that has been built. After it is called, the MapReprBuilder should no longer be used.

func (*MapReprBuilder) WritePair

func (b *MapReprBuilder) WritePair(k string, indent int, v string)

WritePair writes a new pair.

type Pipe

type Pipe struct {
    ReadEnd, WriteEnd *os.File
}

Pipe wraps a pair of pointers to os.File that are the two ends of the same pipe.

func NewPipe

func NewPipe(r, w *os.File) Pipe

NewPipe creates a new Pipe value.

func (Pipe) Equal

func (p Pipe) Equal(rhs interface{}) bool

Equal compares based on the equality of the two consistuent files.

func (Pipe) Hash

func (p Pipe) Hash() uint32

Hash calculates the hash based on the two consituent files.

func (Pipe) Kind

func (Pipe) Kind() string

Kind returns "pipe".

func (Pipe) Repr

func (p Pipe) Repr(int) string

Repr writes an opaque representation containing the FDs of the two constituent files.

type PseudoStructMap

type PseudoStructMap interface{ Fields() StructMap }

PseudoStructMap may be implemented by a type to derive the Repr, Index, HasKey and IterateKeys operations from the struct map returned by the Fields method.

type RConcatter

type RConcatter interface {
    RConcat(v interface{}) (interface{}, error)
}

RConcatter wraps the RConcat method. See Concat for how it is used.

type Reprer

type Reprer interface {
    // Repr returns a string that represents a Value. The string either be a
    // literal of that Value that is preferably deep-equal to it (like `[a b c]`
    // for a list), or a string enclosed in "<>" containing the kind and
    // identity of the Value(like `<fn 0xdeadcafe>`).
    //
    // If indent is at least 0, it should be pretty-printed with the current
    // indentation level of indent; the indent of the first line has already
    // been written and shall not be written in Repr. The returned string
    // should never contain a trailing newline.
    Repr(indent int) string
}

Reprer wraps the Repr method.

type Scanner

type Scanner interface {
    ScanElvish(interface{}) error
}

Scanner is implemented by types that can scan an Elvish value into itself.

type Stringer

type Stringer interface {
    // Stringer converts the receiver to a string.
    String() string
}

Stringer wraps the String method.

type StructMap

type StructMap interface{ IsStructMap() }

StructMap may be implemented by a struct to mark the struct as a "struct map", which causes Elvish to treat it like a read-only map. Each exported, named field and getter method (a method taking no argument and returning one value) becomes a field of the map, with the name mapped to dash-case.

The following operations are derived for structmaps: Kind, Repr, Hash, Len, Index, HasKey and IterateKeys.

Example:

type someStruct struct {
    FooBar int
    lorem  string
}

func (someStruct) IsStructMap() { }

func (s SomeStruct) Ipsum() string { return s.lorem }

func (s SomeStruct) OtherMethod(int) { }

An instance of someStruct behaves like a read-only map with 3 fields: foo-bar, lorem and ipsum.

type ValueTester

type ValueTester struct {
    // contains filtered or unexported fields
}

ValueTester is a helper for testing properties of a value.

func TestValue

func TestValue(t *testing.T, v interface{}) ValueTester

TestValue returns a ValueTester.

func (ValueTester) AllKeys

func (vt ValueTester) AllKeys(wantKeys ...interface{}) ValueTester

AllKeys tests that the given keys match what the result of IterateKeys on the value.

NOTE: This now checks equality using reflect.DeepEqual, since all the builtin types have string keys. This can be changed in future to use Equal is the need arises.

func (ValueTester) Assoc

func (vt ValueTester) Assoc(key, val, wantNew interface{}) ValueTester

Assoc tests that Assoc'ing the value with the given key-value pair returns the wanted new value and no error.

func (ValueTester) AssocError

func (vt ValueTester) AssocError(key, val interface{}, wantErr error) ValueTester

AssocError tests that Assoc'ing the value with the given key-value pair returns the given error.

func (ValueTester) Bool

func (vt ValueTester) Bool(wantBool bool) ValueTester

Bool tests the Boool of the value.

func (ValueTester) Equal

func (vt ValueTester) Equal(others ...interface{}) ValueTester

Equal tests that the value is Equal to every of the given values.

func (ValueTester) HasKey

func (vt ValueTester) HasKey(keys ...interface{}) ValueTester

HasKey tests that the value has each of the given keys.

func (ValueTester) HasNoKey

func (vt ValueTester) HasNoKey(keys ...interface{}) ValueTester

HasNoKey tests that the value does not have any of the given keys.

func (ValueTester) Hash

func (vt ValueTester) Hash(wantHash uint32) ValueTester

Hash tests the Hash of the value.

func (ValueTester) Index

func (vt ValueTester) Index(key, wantVal interface{}) ValueTester

Index tests that Index'ing the value with the given key returns the wanted value and no error.

func (ValueTester) IndexError

func (vt ValueTester) IndexError(key interface{}, wantErr error) ValueTester

IndexError tests that Index'ing the value with the given key returns the given error.

func (ValueTester) Kind

func (vt ValueTester) Kind(wantKind string) ValueTester

Kind tests the Kind of the value.

func (ValueTester) Len

func (vt ValueTester) Len(wantLen int) ValueTester

Len tests the Len of the value.

func (ValueTester) NotEqual

func (vt ValueTester) NotEqual(others ...interface{}) ValueTester

NotEqual tests that the value is not Equal to any of the given values.

func (ValueTester) Repr

func (vt ValueTester) Repr(wantRepr string) ValueTester

Repr tests the Repr of the value.

Package vals imports 18 packages (graph) and is imported by 7 packages. Updated 1 week ago.

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